This is a nice short lesson on playing the drawbars. We should be able to apply Martin's technique on any PSR/Tyros with organ flutes, although drawbar sliders make it easier to play the drawbars. I'm going to try this on Reface YC, too.

Around 11:20, Martin demonstrates the Genos drawbar organ. I dug his short noodle, and wrote down the drawbar settings: